diff --git a/app/Http/Controllers/Api/V1/WelfareController.php b/app/Http/Controllers/Api/V1/WelfareController.php
index 64795f48..055bfcdd 100644
--- a/app/Http/Controllers/Api/V1/WelfareController.php
+++ b/app/Http/Controllers/Api/V1/WelfareController.php
@@ -61,14 +61,18 @@ public function detail(Request $request): JsonResponse
             : 0.05;
         $year = $request->query('year') ? (int) $request->query('year') : null;
         $quarter = $request->query('quarter') ? (int) $request->query('quarter') : null;
+        $startDate = $request->query('start_date');
+        $endDate = $request->query('end_date');
 
-        return ApiResponse::handle(function () use ($calculationType, $fixedAmountPerMonth, $ratio, $year, $quarter) {
+        return ApiResponse::handle(function () use ($calculationType, $fixedAmountPerMonth, $ratio, $year, $quarter, $startDate, $endDate) {
             return $this->welfareService->getDetail(
                 $calculationType,
                 $fixedAmountPerMonth,
                 $ratio,
                 $year,
-                $quarter
+                $quarter,
+                $startDate,
+                $endDate
             );
         }, __('message.fetched'));
     }
diff --git a/app/Services/WelfareService.php b/app/Services/WelfareService.php
index 6231f9f2..683ba0d5 100644
--- a/app/Services/WelfareService.php
+++ b/app/Services/WelfareService.php
@@ -498,7 +498,9 @@ public function getDetail(
         ?int $fixedAmountPerMonth = 200000,
         ?float $ratio = 0.05,
         ?int $year = null,
-        ?int $quarter = null
+        ?int $quarter = null,
+        ?string $startDate = null,
+        ?string $endDate = null
     ): array {
         $tenantId = $this->tenantId();
         $now = Carbon::now();
@@ -562,8 +564,10 @@ public function getDetail(
         // 3. 항목별 분포
         $categoryDistribution = $this->getCategoryDistribution($tenantId, $annualStartDate, $annualEndDate);
 
-        // 4. 일별 사용 내역
-        $transactions = $this->getTransactions($tenantId, $quarterStartDate, $quarterEndDate);
+        // 4. 일별 사용 내역 (커스텀 날짜 범위가 있으면 해당 범위, 없으면 분기 기준)
+        $txStartDate = $startDate ?? $quarterStartDate;
+        $txEndDate = $endDate ?? $quarterEndDate;
+        $transactions = $this->getTransactions($tenantId, $txStartDate, $txEndDate);
 
         // 5. 계산 정보
         $calculation = [